Shiva Purana
अन्ये च ये न जानन्ति विधानं स्मरणं परम् ॥ नमश्शिवाय मंत्रेण ध्यायंतश्शंकरं स्थिताः ॥ ४९ ॥
Those who did not know the great rite remained meditating on Śiva with the five-syllabled mantra “Namaḥ Śivāya”.
english translation
anye ca ye na jAnanti vidhAnaM smaraNaM param ॥ namazzivAya maMtreNa dhyAyaMtazzaMkaraM sthitAH ॥ 49 ॥
hk transliteration by Sanscript